4587b9134491d7a40c0fb467ee8f7cc00c66b91c

When the CommandFailed exception was added it was only being used by the CLI tests. However, it is generally useful for anything that is using subprocess to make external calls. This patch moves it to tempest.exceptions to make using it simpler for non-cli tests to use the exception. Change-Id: Ibf5f1cbbb847d32976b54c4484acfc3c0e3b4f48
Description
RETIRED, further work has moved to Debian project infrastructure